This Tibetan mastiff could probably swallow that girl in one bite, but he doesn't because he's a good boy. Yes he is! A very good boy!

Tibetan mastiffs are some of the world's largest dogs, standing more than two feet tall and weighing up to 150 pounds. Yeah, that's a big pooch. Fortunately they're also quite patient with kids, as you can see here. His name is Simba and the girl's name is Weiwei and they are best pals. Sometime in the next few years, she'll be as big as he is. Or not. In fact, probably not.

More on the majestic Tibetan mastiff here: